Rotary compressor



Dem- 2, 1941. J. c. BUCKBEE 2,264,616

' ROTARY COMPRESSOR Filed Sept 21, 1958 3 Sheets-Sheet l Jbfin EEL/CkbEEDec. 2, '1941. J. c. BUCKBEE 2,264,616 7 ROTARY COMPRESSOR Filed Sept.21, 1938 3 Sheets-Sheet 2 JU/W 5 EMS/(DEE Dec. 2, 1941. J. c. BUCKBEE 2,

I RbTARY COMPRESSOR Filed set. 21, 1938 j :s Sheets-Sheet s CEL/EkbE asany/m4 ditions.

ao'rr oonnsson.

John C. Backhoe, Los Aug-elm, Qa. Application September 21, 1938, SerialNo. 23%,985

12 Claims.

This invention relates to rotary pumps and engines oi the type in whicha cylindrical rotor having radially slidable vanes is eccentricallymounted in a, cylindrical casing. The particular design disclosed hereinis adapted for use as an air pump but it will be understood that variousfeatures of the invention may also be employed in rotary engines andmotors.

. A broad object of the invention is to provide improved lubrication ina rotary machine of the type referred to.

Another object is to reduce vibration and promote smooth operation ofsuch devices.

Another object is to provide a practicable rotary engine or pumpstructure of the vane type in which an efiective fluid seal between therelatively movable parts can be readily produced and maintained.

Another object is to promote the efliciency of a rotary pump operatingunder varying load con- The manner in which the foregoing objects areachieved will be explained by describing in detail, with referenceto thedrawings, theconstruction and operation of an air, pump in accordancewith the invention, it being understood that various changes andadaptations of the particular structure disclosed may bemade withoutdepartv ing from the invention.

In the drawings:

Fig. i is a partial plan view showing in general exterior aspect an airpump constructed in accordance with the invention;

Fig. 2 is a vertical longitudinal section through thepump, the sectionbeing taken in the plane H-H oi Fig.1;-

Fig. 2A is a sectional view similar to Fig. 2,

v but on a larger scale and showing only one endportion of the pump;

Fig. 3 is a cross section through the pump taken in the plane I11.lII ofFig.1; and

Fig. 4 is a detail inside face view of an adjusting end plate of theunit.

Referring to the drawings, the air pump therein disclosed comprises a.casing member I of roughly cylindrical shape, which is stationarilysupported on a suitable base 2 and is provided with an'inner cylindricalsurface 3 constituting one of the walls of a compression chamber. .For

convenience the member i will'hereinafter be referred to as the stator.The stator I may be provided with a water passage t for coolingpurposes.

The opposite ends of the stator l are closed. A by heads a and .8.respectively, which may be bolt- 55 line. it in Fig. 3), at an angle tothe horizontal,

which in turn rotatably support a shaft l on which a cylindrical rotor 8is mounted, the rotor being positioned eccentrically within the casing5' 3. The heads 5 and 8 may also have passages 3 therein for thecirculation of cooling liquid.

The rotor 8 is of smaller diameter than the inner surface 3 of stator iand is positioned eccentrically within the statorso that its peripheryapproaches very close toth'e inner surface 8 of the stator i at onepoint so as to provide for effecting a, fluid seal between the rotor andcasing along the line where they most nearly approach. The rotor 8 isprovided with a plurality of radial slots t extending, from end to endof the rotor, in which slots there are slidably mounted vanes I0. Inoperation, the rotor is rotated at relatively high velocity so that thevanes it are urged outward toward the inner surface 3 of'the stator bycentrifugal force. The stator i is provided with an inlet port it on oneside and an outlet port :2 on the other side so that when the rotor isrotated in clockwise direction (referring to Fig. 3), the air or othergas to be pummd, which enters through the inlet port it is trapped inthe pocket created between the vanes it and between the surface of therotor and the surface 3 of the casing, and is carried around-with therotor and compressed as the rotor surface ap- 30 proaches the casingsurface, and finally discharged through the port 12.

Insofar as the general structure so far described is concerned, it is inaccordance with the general type described is that they tend to vibratedue to the fact that under varying conditions of load,

varying radial forces are applied in different directions to the rotor.Thus under conditions of 40 no load the chief force acting upon therotor is.

gravity, which of course exerts a downwardly directed force. On theother hand when a pump of older design of the type described is working,new forces are developed which act radially on the rotor in directionsother than downward, so that they oppose the force of gravity, sometimes exceeding it, and at other times being less than it. These varyingradial forces tend to shift the rotor and shaft. throwing undesirablestrain on the bearings and often causing severe vibration.

In accordance with the present invention, I

greatly reduce the vibration resulting mm the 1 with the line of closestapproach of the rotor to the casing closely adjacent to the lower partof outlet port l2. With this construction the forces resulting from thecompression of gas between the upper surface of the rotor and thejuxtaposed surface of the casing act in a general downwardly directionon the rotor, thereby holding the rotor shaft firmly in its bearings,avoiding vibration and chattering in the bearings, and giving a smooth,quiet-running machine.

The fact that the compression of the gas takes place on the upper sideof the rotor also facilitates free entry of air or gas into and out ofthe machine, further reducing vibration of the machine by minimizingeddy currents of air or gas within the machine and contributing to itssmooth operation and efliciency. Other advantages of the particularorientation of the rotor as shown will be discussed later in connectionwith the lubricating system of the machine.

In a machine of the type disclosed, it is desirable that the ends of therotor and the vanes be liquid sealed with respect to the casing as wellas that the outer edges ofthe vanes 10 be so sealed with the. innersurface 3 of the casing. Heretofore, to the best of my knowledge, it hasbeen the practice to carry the ends of the rotor out to contemplatedrunning clearances with the heads of the casing, the actual clearance inoperation being determined by the thickness of the gaskets placedbetween the ends of the cylindrical casing and the heads, and by theextent to which the bolts holding the heads in place were tightened.This was obviously a crude and uncertain method of construction whereclearances measured in thousandths of an inch must be secured andmaintained to secure efficiency.

In the machine disclosed, I permit of accurate adjustment of theclearance between the ends of the rotor 8 and vanes l and the abuttingsurfaces of the casing by providing separate inner head members l andI6, respectively, which are slidably mounted in counterbores I1 and I8,respectively, in the opposite ends of the casing member 3. Thesecounterbores extend inwardly from the ends of the casing 3 substantiallybeyond and into overlapping relation with the ends of the rotor B. Theheads I5 and I6 are provided with apertures l9 and 20, respectively, forthe passage of the rotor shaft 1 and for admitting lubricant to the vaneslots 9, and are machined to closely approach the end faces of the rotorand the ends of the vanes H! to provide for effecting a fluid sealtherewith.

As previously indicated, the inner heads l5 and I6 are slidably mountedwithin the counterbores I1 and I8 and must therefore be retained indesired longitudinal positions with respect to the shoulders of the saidcounterbores and the rotor 8. I provide for accurate longitudinaladjustment of the inner heads I5 and I6 and the locking of the saidheads against outward movement from thedesired position of adjustment bymeans of several plungers 2| which are disposed at convenientcircumferential intervals back ofv heads 15 and I6, and extend throughlongitudinal apertures provided therefor in the outer heads 5 and 6,respectively, into abutment with the outer faces of the inner heads l5and I6. The outer ends of the apertures in the' heads 5 and 6 whichreceive these plungers 2| are threaded to receive screws 22, the innerends of which screws bear against the outer ends of the plungers 2|. Itwill be obvious that by adjustment of screws 22 the heads [5 and I6 maybe adjusted to desired longitudinal positions within said counterboresand maintained against outward movement from those positions.

To limit inward movement of the heads l5 and 16 from their positions ofdesired adjustment, each of the heads l5 and I6 is provided with aperipheral flange 23, the inner end face of which seats against anadjustment ring 24 which'in turn seats against the shoulder-at the endof the counterbore H or I8, as the case may be. By suitably choosing thelongitudinal thickness of the rings 24 and adjusting the screws 22 toforce the inner heads l5 and I5 up snugly against the rings 24, thedesired accurate clearance between the ends. of the rotor and the headsl5 and I6 may be readily obtained. The clearance necessary in anyparticular case will depend to a large extent upon the temperaturevariations in the pump, which cause varying expansion of the parts, andpumps constructed as described can be adapted for different conditionsof operation involving different operating temperatures by merelychanging the spacer rings 24.

It may be desirable in many instances to form the plungers 2| of amaterial having a greater rate of expansion for a given temperature risethan the stator material, so that after the machine has been startedcold'the increase in temperature during operation increases the pressureof the plungers 22 against the inner heads l5 and 16.

The adjustment rings 24 have their inner surfaces flush with the surface3 of the stator. The spaces within the flanges 23 are provided withaccurately machined floating rings 25 which receive the radial thrust ofthe vanes 10 due to centrifugal force, and rotate with the vanes. Thefloating rings 25 within the flanges 23 are bored slightly smaller indiameter than the stator surface 3 and the blades ID are thereby heldclear of the stator surface 2 when the machine is in operation, and wearbetween the vanes and the stator surface 3 avoided. Floating rings havebeen used before to limit outward movement of vanes in rotary machinesof the type with which this invention is concerned, but to the best ofmy knowledge it has been the practice in the past to position such ringsin counterbores in the stator some distance in from the stator ends,which construction requires theplacing of stationary rings between thefloating rings and the end heads to complete the stator bore from thefloating rings out to the end heads. Such construction was objectionablein that it was expensive and in a measure uncertain as to the degree ofclearances obtainable. By placing the floating rings 25 at the endsofthe rotor 8 within the flanges 23 of the inner heads I5, I provide avery simple construction for obtaining very accurate and definiteclearances. Thus it is merely necessary, prior to insertion of the headsl5 and I6 into the stator, to position the floating rings 25 within theflanges 23 and check the widths of the rings 25 by observing whethertheir end faces are clear of the end faces of the flanges 23. If theyhave the clearance required for successful operation, it is then knownthat when the inner heads and rings are assembled in the stator thelongitudinal clearances at the edges of the rings will be correct.

In the pump as so far described, the inner end walls l5 and I6 arefitted to very close clearances with the ends of the rotor and vanes.However the interior end walls l5 and 16 are not intended to take anythrust that may be apaccepts 3 plied by Justable porting the tudinaldisplacement.

I prefer to employ antifriction bearings for supporting the rotor, andto facilitate adjustment and provide for longitudinal expansion of thethe rotor, and I provide a readily adbearing construction for accuratelysuprotor, I employ a longitudinally adjustable com-1 bined radial andthrust bearing at one end and a radial bearing only at the other end ofthe rotor.

Referring to Fig. 2, the radial. bearing is positioned at the left endof the rotor 8 and is of the roller type; thus it comprises an innerrace .21 mounted on the rotor and rigldlysecured in position against ashoulder 28 on the shaft by.

a nut 29 threaded onto the shaft. The race 2'!v is provided with anannular recess the sides of which bears against the ends of a pluralityof cylindrical rollers 39 which may be confined in a cage in accordancewith the usual practice. The rollers 3d bear against a stationary outerrace 3! which is cylindrical on its inner surface so that the rollers 3@can move freely longitudinally with respect thereto. The race 3i isclamped in the outer head 5 of the pump by a closure member 32, whichclosure member alsoincorporates packing material 33 and a packing gland3 for effecting a seal about the shaft F. It will be observed that thishearing rotatably supports the shaft 7 against any radial movement butpermits free longitudinal movement between the rollers 88 and the outerrace 3t. r

The hearing at the other end of the rotor (the right end in Fig. 2) isadapted to resist both radial and longitudinal movement of the rotorwhile permitting free rotation thereof, and, as shown, is of the halltype. Thus it comprises an inner race 35 rigidly clamped on the shaft 5against a shoulder thereon by a nut 37. The outer surface of the innerrace 35 is grooved to receive a ring of balls 38 which also fit in ajuxtaposed groove in the inner wall of an outer race 39. By virtue ofthe grooves in the inner and outer races, the races are restrainedagainst longitudinal as well as radial movement with respect to eachother. The outerrace. ts-i rigidly secured by a threaded bushing at in acage (ll,

which cage is provided with an outer cylindrical surface at ground toslidably fit in a cylindrical recess in the head 5. Adjacent its outeredge the cage t! is provided with exterior threads 45 and cooperatingthreads are provided on the inner surface of the recess in the head 6 atits outer end. Therefore by rotating the cage 6i the cage and the ballhearing may be shifted longitudinally to adjust the rotor 8 to thedesired position oi clearance with'respect to the inner heads i5 and 65,respectively.

To look the cage M in a desired position of adjustment a pin t3 isprovided in the bushing dd, this pin projecting longitudinally from thebushing into one of a plurality of recesses provided in. an end plate Mwhich closes the end of the head 6. It is to} be understood that thebushing dd, after being screwed up tight against the outer race 39, islocked against further rotation with respect to the cage M, as bypassing a pin dta through registering apertures in the cage and bushing.Hence the pin 43 restrains the bushing from rotation and the bushing inturn restrains the cage ill from rotation.

Referring to Fig. 4, which is a view of the innerface of the closureplate 5d, it will be obrotor against both radial and longivided in theplate for reception of the pin 53 so that the cage 4| can be locked atsuch position as longitudinal adjustment of the rotor may require.Longitudinal adjustment of the rotor to the desired running position iseffected by remov,-.

ing the cover plate 44 and rotating thecage 4| in one direction untilthe end of the rotor bears against one of the inner head members IE orit. The cage 4| is then rotated in the opposite direction until therotor bears against the other inner head.- Then either by micrometergauge rea'dings or through knowledge of the number of threads per inchon thecage and observing the angle through which the cake M has been t din the above operation, the total clearance between the ends of therotor and the faces of heads I5 ii the and It may be readily determinedas well as the relative position of heads 55 and it with respect to therotor, and it is then merely a matter of again rotating cage dl to movethe rotor longitudinally until the desired running clearance at therotor ends is obtained. after which case ti is looked through the mediumof pin t3.

When a pump of the type described is rotated continuously to supply avarying demandjand the demand decreases, the pressure in the dischargeport rises beyond the desired value and lessly wasted. I avoid thisobjectionable feature by providing a special valve system for cuttingoiithe supply of air to the pump and venting the discharge side of thepump to the atmosphere whenever thepressure in the discharge portexceeds a desired value.

Thus referring to Fig.3, the inlet passage i l. leading into the statorl, communicates throu h a plurality of ports he with a central passage5! which in turn is connected-at its upper end to an intake pipe 52. Apiston valve 53 is slidably fitted in the passage ti and may be providedwith piston rings 56 at its upper and lower edges for effecting 'afluid-tight seal against the walls of the passage 5!. When the valve 53is in lowermost position, as shown in Fig. 3, its upper end issubstantially flush with the lower edges of the ports, so that the pipe52 is in free communication with the intake passage it. However, whenthe valve 53 is in uppermost position in the passage iii, it isjuxtaposed to the ports 58 and blocksthe -iiow of air therethrough. Thevalve 53 normally remains in the lowermost position shown in Fig. 3, inwhich the ports, 56 are open. When it is desired to close the ports lidthe valve 58 is raised to its uppermost position by introducing fluidunder pressure to the passage 51' below valve 53.. The fluid employedfor liftserved that a plurality of apertures 68 are pro- 75 log thevalve 53 may be air under pressure from the discharge side of the pump.and is delivered through a pipe under the control of a valve mechanismnext to be described.

Referring to Fig. 3, the discharge passage 02' in the stator Icommunicates through an orifice 58 with a chamber 57 having a dischargepassage 58 extending from the .upper side thereof into communicationwith. a discharge pipe 59. A

check valve 80, which is urged into closed position by a spring 5|,serves to cut the passage 58 oil from the pipe 59 in response to anyreturn how of air. The'passage 58 is incorporated in a block 62, whichalso has formed therein, to one side of the passage 5d, a cylinder 63,which slidably contains a piston element 64. .A'second piston elementis'attached to and spaced above the piston element 66, the two beingformed in- Y tegral with each othenand with a push recite punfpcontinues to work, power is need-.

' At the same time extendingbelow the piston 64. The pistons 65 and 65are normally maintained in an upper position, as shown in Fig. 3, by ashort arm 61 supporting a roller 6.8, which bears against the lower endof push rod 66. The short arm 61 is attached to a shaft ll journaled inbearings in the block 62, as shown in Fig. l. The shaft II also hasattached to it a long arm 69 carrying a weight 10. A short stop arm 12is attached to the shaft II for limiting downward movement of the shortarm 61.

A passage 15 connects the discharge pipe 58 permanently with the upperend of cylinder 63, and a passage 16 permanently connects the passage 58with the cylinder 63 at a point in the latter juxtaposed to the piston64 when the latter is in uppermost position, as shown. Aventcommunicates the central portion of the cylinder 83 with theatmosphere under normal conditions. A pipe 55 also communicates with thecylinder 63 at a point a short distance above the vent 11.

Under normal conditions of pump operation, 8

and 65 occupy the positions shown in Fig. 3, and the arm 69 occupies theposition shown in full lines in Fig. 3. Under these conditions pressurein the discharge pipe 58 is applied through passage 15 to the upper endof piston 65, tending to force the piston down, against the forceexerted thereon by the weight 10 acting through arm 68, shaft H and theshort arm 81, and the piston 64 seals the outer end of the passage 16.The condition described will obtain whenever the pressure in thedischarge pipe 59 is insufficient to overcome the force of the weight10, and with the pistons 65 and 64 in the upper position shown, thepassage 15 is sealed and the pipe is connected to the vent 11 so thatatmospheric pressure exists below the inlet valve 58, permitting thelatter to remain in its lowermost position and air to flow freely intothe inlet When the consumption of air supplied through the dischargepipe 59 is reduced so that the pressure rises sufficiently to force thepistons 65 and 64 downwardly, thereby swinging the arm 68 into theposition shown in dotted lines in Fig. 3, the downward movement of thepistons carries the upper edge of the piston 65 below the passagecommunicating with the pipe 55, and carries the upper edge of the piston64 below the passage 16. Therefore air under high pressure from thedischarge pipe '59 flows through'passage 15, the upper end of thecylinder 63, and into andthrough the pipe 55 to raise the intake valve53 into uppermost position, in which it closes the ports 50. This cutsoff the supply of air to the intake passage H and the compressor ceasesto pump air. the movement of the piston 64 communicates the passage 16with the vent 11 so that any pressure in the outlet passages l2 and 56and the chambers 51 and 58 is relieved. It is understood, of course,that as soon as flow ofair from passage 58 to the discharge pipe 59ceases, the check valve 60 closes to prevent return flow.

When the pressure in the dischargepipe58 drops below an amountsuflicient to overcome the force of the weight 10, the weight I0 swingsthe arm 69 back into the full line position, raising the pistons 64 and65 into uppermost position, in which the pipe 55 is vented to theatmosphere, and the passage 16 is closed. Thereupon the inlet valve 53drops into lowermost position, opening the ports 50, and the pumpingoperation is the pistons 64 resumed.

It will be observed from Fig. 3 that the normal position of the long arm69 extends upwardly and outwardly from shaft II at a relatively largeangle from the vertical, but that in the dotted line position the arm 69makes a much smaller angle with the vertical. Obviously the torqueapplied to the shaft II by the weight 18 is substantially greater whenthe arm 69 is in the full line position than when it is in the dottedline position. Hence a substantially greater pressure in the dischargepipe 59 is required to stop the pumping action than to resume it. Thisis desirable because it prevents unnecessarily frequent starting andstopping of the pumping action. Thus the above described controllingdevice may be adjusted to cut out the pumping action when the terminalair pressure in the discharge pipe 59 reaches, say, 35 pounds per squareinch and not cut in again until the pressure falls to 30 pounds persquare inch. Various desired differentials between the pressure requiredto stop the pumping action and that permitting resumption of the pumpingaction may be obtained by adjusting the radial position of the arm 69on'the shaft H. As shown in Fig. 1, the arm 69 is locked to the shaft'II by a set screw 19. By loosening the screw 19 the radial position ofthe arm 89 relative to the shaft H may be altered to vary the relativepressures at which the compressor cuts in and cuts out of service.

In a rotary compressor, particularly compressors operating at highspeeds, it is essential to provide a positive supply of oil to thevarious working surfaces in order to reduce friction and in many partsto help maintain a seal.

The present invention incorporates a novel and particularly effectiveoiling system which will now be described.

Referring to Figs. 2 and 3, there is mounted on the upper side of thestator i, an oil reservoir which, as shown, happens to be secured to thestator by a water pipe 8| which extends downwardly therethrough andcommunicates with the water passage 4 for cooling the compressor.However, there is no communication between the interior of the waterpipe 8| and the reservoir 88, the pipe 8| functioning only to retain thereservoir in position. The reservoir 80 supplies oil, through a valvemechanism, later, and a pair of pipes 82, to opposite ends of thecompressor. Each pipe 82 is connected through a sight feed regulatingvalve 83 and an elbow 84 to a conduit 85 extending through the endmembers 32 and 44, and the outer heads 5 and 6. Thus the conduits 85terminate in orifices 86, 86 which are positioned within the openings l9and 20, respectively, in the inner heads l5 and [6, respectively. Theseorifices 86 at the discharge ends of the conduits 85 face in thedirection of the windage stream created by the rotor and are so shapedthat the windage created by the rotor tends to suck or draw oil fromtheconduits 85.

When the compressor is in operation, oil flows by gravity from thereservoir 80 through the pipes 82 and the sight feed regulating valves83 and through the conduits 85, and is discharged through orifices 86into the annular spaces I9 and 20 in heads [5 and I6. The rotor isprovided at each end with an annular groove 81 which extends to thebottoms of the vane slots 9. The oil therefore flows from the annularspaces I8 and 20 into the annular grooves 81 and thence into the slotsback of the vanes as the vanes move outwardly in the slots, and later,when the vanes to be described openers lubricate the ends of vanes I andto help seal the ends of the rotor and the surfaces of heads I and it.

,A baflie plate 88 is preferably positioned on the outer surface of each'of the inner heads I5 and it, these plates having openings throughwhich the orifices 85 project into the annular spaces I9 and to in theheads I5 and I 6, and through which the shafts 7 project. These bafliesintercept the oil that may splash out of the rotor slots 9 when thevanesdescend in the said slots and return most of it to the annulargrooves 81 in the ends of the rotor, but some of the oil works outwardlyalong shafts l and lubricates the bearings at each end of the rotor, andsome of the oil also drops the air before the air discharged from thecompressor, notonly to eliminate oil'from the air delivered, but torecover as much of the oil as possible for reuse. To this end a pocket9| is formed in the chamber 51, juxtaposed to the discharge orifice 56,so that the mixture of oil and air escaping from orifice 50 is directed'into I the pocket 9|. In order for the air to escape from pocket 9|into chamber 5l it has to reverse its direction of flow and pass outbetween the rim of the pocket 9| and the edges of the orifice 56. As aresult of this sharp change in the direction of the'fiow of the airwithin the pocket 9|,

down in the space between the inner head l5 and the outer head 5, andbetween the inner head I0 and the outer head 6, and flows throughchannels 88a in the lower edges of the heads i5 and it to the undersides of the floating rings 25. The floating rings have numerous pockets2511 on their outer face and these pockets pick up oil received throughchannels 8811, asthe rings 25 rotate in service, thereby materiallyimproving the lubrication of said rings.

When the pump is being operated as a compressor. the pressure adjacentthe ends of the rotor is considerably above atmospheric, due tovunavoidable leakage past the ends of the rotor.

Such pressure would interferewith free gravi tational flow of oil fromthe reservoir 80 through the pipes 82. To equalize the pressure in thereservoir, I therefore provide an air tube 89 which communicates thespace within the head 6 with the upper spaceof the reservoir 80. Thisinsures equal pressures above and below the oil in the reservoir anduniform gravitational flow of oil from the reservoir through theconduits 85 into the compressor.-

Referring now to Fig. 3, it will be noted that the inlet port H is sopositioned with respect to the rotor that excess oil escaping from therotor slots accumulates in the bottom of the inlet port ii in thestator, creating a pool of oil therein. The lower edges of the ports 50,communicating the passage 5i with the port II,

are positioned a substantial distance above the bottom of the port II soas to permit a substantial pool of this oil to accumulate withoutoverflowing into the intake passage 5I The bottom of the port I Ipreferably extends substantially horizontally and tangentially withrespect to the lowermost portion of therotor. Therefore as the rotorrotates at high speed in a clockwise direction (the direction ofrotation being taken with reference to Fig. 3), the outer edges of thevanes whip the oil in the pool in the ports I I' and splash it into theintake passage so that the oil is finely broken up and carried into andthrough the compressor with the air stream. This flow of oil through thecompressor not only. helps to maintain proper lubrication between themoving parts but carries away dirt that might otherwise tend toaccumulate within the pump. The mixture of air and oil is dischargedfrom the pump proper through port I2, the lower inner edge of which ispositioned well above the bottom ofthe port so spent oil and dirt cannot flow back and foul the rotor. a

It is very desirable to separate the oil from walls to the bottom of thepocket where it es-' capes through a vent 92 into a sump 93 in thebottom of chamber 51. To reduce as much as possible the quantity of oilthat tends to follow the air stream out of the pocket, the mouth of thepocket is preferably provided with an inturned flange 9a which trapsexcess oil and carries it to the bottom of thepocket and into the vent92.

An oil return tube 95 extends from the bottom of the sump 93 up to anoil filter 95. Another tube 91 extends from the outlet of the oil filterto the top of the oil reservoir 80. Communication between the sump 93and the tube 95 is regulated by a float valve 98 operated by a float.Whenever the oil rises in the sump above a pre- 90, whereupon oil isdischarged from the sump through the filter 95 to the reservoir byvirtue of the fact that the pressure existing in chamber 5'? and sump93. is greater than the pressure in the oil reservoir. When the oildrops to a desired minimum level in the sump 93 the float valve 98 stopsthe flow or oil therefrom.

By virtue of the fact that when the pump is in operation the pressurewithin the ends of the compressor and theoil reservoir 80 is usuallyabove atmospheric, 1 find it desirable to provide an automatic valvethrough which the reservoir 80 may be refilled as necessary withoutdanger of the hole through which it is filled being accidentally leftopen, as such an accident would result in failure of the oiling systemto operate. This valve comprises. a cylinder I00 formed within thereservoir 80' and in communi:

cation with the interior thereof through a vent I 0lin the lower end anda port I02 in the side. A piston I03 is slidably mounted in the cylinderI00, which piston is normally maintained in up-' permost position inwhich it blocks the port I02,

. by aspring I04 compressed between the piston and the lower end of thecylinder I00. The piston I03 is provided with a stem I 05 extending upthrough and beyond the .upper end of the cylinder. The upper end of thecylinder is normallyrclosed by a. screw cap I06 having a reentrantrecess therein for clearing the valve stem I05. To replenish the oilsupply in the reservoir, the cap I06 is removed, the stem I05 depressedto push the piston I03 clear of the port I02, and oil poured.in. Thestem I05 is then released, and the filler cap I05 replaced.

whether or not the compressor was operating.

. and comprises a cylinder Obviously when the compressor is notoperating there would be no pressure in the chamber 51 to restore theoil to the reservoir, with the result that the entire mechanism mightbecome flooded with oil. I prevent possibility of such flooding byproviding an automatic control valve interconnecting the reservoir 80with the feed pipes 82. This valve construction is shown in Fig. 3, I01formed in the wall of the reservoir 80, which cylinder communicates,adjacent its lower end, with the reservoir 80 through port H0, and,adjacent its upper end through a pipe I08, with the intake passage II ofthe compressor. The cylinder I01 contains a weighted piston valve I09,which, when in lowermost position, covers the ports leading to the pipes82, but has its lower end positioned above the port leading to thereservoir 80. The piston valve I09 is connected by a stem H2 to a weightII3 for normally maintaining the valve in lowermost position. The upperend of the cylinder I01 is closed with a casing II l, which encloses theweight I I3 and seals the upper end of the cylinder from the atmosphere.

When the pump is not in operation, the pressure within the reservoir 80is substantially atmospheric, Likewise, the pressure in the intakepassage II is substantially atmospheric, Therefore, the pressures actingon the upper and lower surfaces, respectively, of the piston I09 aresubstantially equal, and the piston remains in its lowermost position byvirtue of its weight. In this position, the ports in the cylinder I01connected with the pipes 82 are closed, so that oil can not flow fromthe rservoir to the compressor.

However, when the pump is placed in operation, the pressure in theintake passage II is reduced, and the pressure in the reservoir isincreased by virtue of the fact that certain leakage of air occurs pastthe rotor into the end spaces of the compressor, increasing the pressurein such spaces above atmospheric. This increased pressure in the endspace within the compressor is transmitted through the air tube B9 tothe reservoir 60. As a result of the decreased pressure acting on theupper end of the piston I09 and the increased pressure acting on thelower end, the piston is lifted to uncover the ports leading to the oilpipes 82, whereupon normal gravity circulation of oil from the reservoirto the compressor commences and continues as long as the compressor isworking,

When the compressor stops, the pressures within the ends of thecompressor casing and the inlet passage ll equalize, whereupon thepiston I09 drops by its own weight to shut off the oil supply to thepipes 82. Test ports I I5 for attachment of pressure gauges may beprovided at circumferentially spaced intervals in the upper half of thecylinder I, these ports being normally closed by screw plugs IIB.

Cylindrical recesses Ill and 8 may be provided in the passages 15 and 16respectively, for the insertion of cylindrical wire screens to keepforeign matter in the air stream from reaching and fouling the valvecylinder 63.

A valve screw H9, adjustable into and out of the passage 15, ispreferably provided to regulate the rate of flow of air to the upper endof the cylinder 03 and thereby regulate the speed at which the pistons64 and 65 move.

For convenience, the invention has been explained by describing indetail one specific form understood, however, that many changes in thedetails of the particular structure shown can bemade without departingfrom the invention, which is to be limited only to the extent set forthin the appended claims.

I claim:

1. In a rotary machine of the type described, a horizontally disposedcylinder, a rotor eccentrically positioned off vertical center withinthe lower part of said cylinder and having radially slidable vanestherein, bearing means for rotatably supporting said rotor, saidcylinder having inlet and outlet ports upon opposite sides thereof sopositioned that fluid entering the cylinder hrough the intake port anddischarged through the outlet port is compressed between the upper sideof the rotor and the upper side of the cylinder, the plane ofeccentricity of the rotor and stator extending at such an angle from thevertical and the vanes being so arranged that the vertical resultant ofthe fluid pressure forces on the rotor acts downwardly whereby thecompressed fluid acts in the same general direction as gravity to aidgravity in holding the rotor down in the bearings.

2. In a rotary machine of the type described, a stationary casingmember, a rotor eccentrically positioned within said casing member andhaving a radially slidable vane nearly contacting said casing memberwith its outer edge, means for rotatably supporting said rotor in saidcasing member, said casing member having a curved surface for nearlycontacting and sealing with the rotor vane, which surface is shorteraxially than said vaneand rotor, said surface merging into a counterboreportion of larger diameter at one end, an end casing memberlongitudinally slidable in said counterbore portion of said firstmentioned casing member, for completing the compression chamber at theend of the rotor and vane, means for varying the longitudinal positionof said end member in said counterbore to adjust the clearance betweenthe end member and the rotor, and a removable filler ring interposedbetween said end member and the end of said counterbore, said fillerring effecting a seal between the end of said slidable end casing memberand the end of said cylinder casing member, in which said means forvarying the longitudinal position of said end member includesthermo-responsive pins bearing against and extending outwardly from theouter side of the slidable end casing member and anchored with respectto said casing member at their outer ends to compensate for expansionand contraction due to temperature changes and maintain a seal betweensaid slidable end casing member and the end of said rotor in varyingtemperature conditions.

3. A rotary machine of the type described, comprising a stationarycylinder member, a rotor eccentrically positioned therein and having aplurality of radially slidable vanes adapted to nearly contact and sealwith the inner surface of said cylindrical member, means for rotatablysupporting said rotor in said cylinder member, the latter having acentral interior surface shorter than said vanes and rotor and merginginto a counterbored portion of larger diameter at each end, end casingmembers seating in said counterbored portions of said cylindrical memberand completing the compression chamber at the ends of the rotor andvanes, said end casing members having inwardly extending flanges, thsaid of pump incorporating the invention. It is to be flanges havinginner bearing surfaces thereon of larger diameter than the diameter ofsaid interior surface of said cylindrical means, and a vane-retainingfloating ring rotatably mounted within each of said flanges, the innerdiameters of I said rings being slightly less than the diameter of thesaid interior surface of said cylinder member. 4. A machine as describedin claim 3, with means for supplying oil to said floating rings, the

outer surfaces of the rings having circumferentially spaced recessestherein constituting oil pockets.

5. A rotary machine of the type described comprising casing meansforming a rotor chamber having a continuous side wall, and end walls, at

ally supporting one end of said shaft while permitting rotational andlongitudinal movement of the shaft relative to' the casing and bearingmeans for radially and longitudinally supporting the other end of thesaid shaft while permitting free rotation thereof, and means foradjustably supporting said last mentioned bearing means forlongitudinaladjustment thereof relative to said casing, whereby saidrotor can bepositioned with respect to said end walls by longitudinaladjustmentof said last mentioned bearing means and maintained in saidposition, said last mentioned bearing means comprising a cage threadedinto said casing whereby said bearing can be adjusted longitudinally byrotating said cage, and means for fixing said cage in predeterminedposition of rotary adjustment.

6. In combination, a fluid pump having a fluid inlet passage and a fluidoutlet passage, inlet valve means for closing said inlet passage inresponse to fluid pressure applied to said valve means, a check valve insaid outlet passage for preventing return flow through said outlet pas--a pressure equalizing conduit communicating the sage to said pump, and apressure responsive means responsive to predetermined pressure in saidoutlet passage beyond the said check valve therein for applying fluidpressure to said inlet valve means and actuating the latter to closesaid inlet passage, said pressure-responsive means comprising acylinder, a piston reciprocable therein and having a face exposed topressure in said outlet passage beyond the said check valve, meansyieldably resisting movement of said piston in response to pressure onsaid face, a duct from said cylinder to said outlet passage at a pointahead of said check valve, a vent duct in said cylinder, said pistonnormally blocking said cyl-- inder between said ducts but moving out ofblocking position in response to said predetermined pressure.

-said vane and the-outer portion of the end of said rotor, a shaft forrotatably supporting said rotor extending therefrom and through anaperture larger than said shaft provided therefor in said inner endwall, an outer end wall sealing and within said aperture in said innerwall, and

space between said inner and outer end walls with the upper portion ofsaid oil reservoir, whereby oil flows by gravity from said reservoirthrough said oil feeding conduit to the rotor ends irrespective of thepressure between said end walls and rotorr 8. A machine as described inclaim '7, in which theopen end of said oil conduit adjacent to the-rotor end is directed in the direction of rotation of said rotor,whereby windage created by the rotor tends to draw oil from the conduit.

9. A machine as described in claim 7, in which said rotor is providedwith an annular recess in the end thereof below the end of said vaneslot whereby oil from said conduit is directed below the vane into thevane slot in the rotor.

10. A machine of the type described comprisinga cylinder, a rotortherein having a radial slot with a vane slidably mounted in said slot,said vane nearly sealing with the cylinder, an end'wall sealing with oneend of said vane and with the outer portion of the one end of saidrotor, a shaft rotatably supporting said rotor extending therefrom andthrough an aperture larger than said shaft provided for the passage ofthe shaft in said end wall, means for supporting said shaft, anoilreservoir, an oil feeding conduit extending from said reservoir to aposition adjacent the end of said rotor within said aperture in saidwall, the outer orifice of said aperture being smaller than the innerorifice thereof, whereby the end of the rotor and the aperture wall forman annular trough for containing 011., e

11. A machine of the type described, comprising a casingmeans forming aninlet passage and an outlet passage, and a mechanism therebetween whichcreates when in operation a higher pressure within said mechanism thaniii the inlet passage, a closed oil reservoir above said mechanism, anoil conduit extending from said reservoir to a point within saidmechanism for delivering oil thereto by gravity flow to lubricate thesame, a pressure equalizing conduit communicating said reservoir withthe interior of said mechanism, and pressure responsive valve means vfor communicating said oil-conduit with said reservoir only in responseto pressure in said reservoir higher than the pressure in said inletpassage, in which said 011 reservoir has a flller opening forreplenishing the oil supply therein,

fluid inlet passage and a fluid outlet passage, in-

with said cylinder and about said shaft, a closed 7 oil reservoir abovesaid cylinder, an oil feeding conduit extending from the lower portion.of said reservoir to a point adjacent the end of said rotor 76 ahead ofsaid check valve,

let valve means for closing said inlet passage in response to fluidpressure applied to said valve means, a check valve insaid outletpassage for preventing return flow through said outlet passage to saidpump, 'a pressure responsive means responsive to predetermined pressurein said outlet passage beyond the said check valve therein for applyingfluid. pressure to said inlet valve means and actuating the latter toclose said inlet passage, said pressure-responsive means comprising acylinder, apiston reciprocable therein and having a face exposed topressure in said outlet passage beyond the said check valve, meansyieldably resisting movement of said piston in response to pressure onsaid face, a duct from said cylinder to said outlet passage at a point avent duct in laid having a weight thereon, said weight being positionedupwardly and outwardly from the fulcrum point of said lever, whereby theforce applied to said piston by said lever arm is greater when saidpiston element is in said first position than when in said secondposition, and a substantially higher pressure in said outlet passage isrequired to move said piston from said first to said second positionthan to retain the piston in the second 10 position.

JOHN C. BUCKBEE.

